Life satisfaction and peace of mind among dentists: a cross-sectional study.

OBJECTIVES: This study sought to identify the factors associated with the life satisfaction and peace of mind (PoM) of dentists not in full-time clinical training. MATERIALS AND METHODS: Cross-sectional questionnaires were distributed to dentists in Taiwan to collect their life satisfaction, PoM, sociodemographic data, and dental career-related characteristics. Life satisfaction was measured using a 5-item Satisfaction with Life Scale. PoM was measured using a 7-item Peace of Mind Scale. Descriptive statistics and multiple linear regression models were estimated to explore potential associations between the two scales and the examined factors. RESULTS: A total of 1196 dentists (45.6% female; mean age = 44.12) completed the questionnaires. The response rate of completed questionnaires from email invitations was 32.9%. On multivariable analysis, life satisfaction and PoM were associated with age (b = 0.008 in both), better perceived health (b = 0.262 and 0.308, respectively), family interaction (b = 0.264 and 0.207, respectively), and friend relationships (b = 0.076 and 0.091, respectively). Being married (b = 0.191), being specialized (b = 0.127), working in private practice, and spending 10 to 39 h per week with patients (b = 0.101 to 0.162) were associated with a higher level of life satisfaction but not PoM. CONCLUSIONS: Specialists working in private practice without working overtime were associated with better life satisfaction. However, the dentists' health and relationships with family were more related to their subjective well-being than their professional achievements. CLINICAL RELEVANCE: Our findings can help policymakers increase awareness of the well-being of general dentists and those in academia or hospitals to promote their mental health.

Life Satisfaction of US-trained Dental Specialists in Taiwan.

OBJECTIVE: A large number of residents in US advanced specialty education programmes are foreign-trained dentists. When faced with the career dilemma of applying for US residency training, foreign-trained dentists may wonder whether it is worth proceeding along that path. In addiditon, studies capturing benefits from receiving US residency training are rare. Therefore, this study compared the life satisfaction amongst 3 dentist groups in Taiwan (ie, US-trained specialists, Taiwan-trained specialists, and general dentists). METHODS: Cross-sectional surveys were distributed to dentists currently residing in Taiwan. Participants were surveyed about demographic information, career-related information, and life satisfaction. Life satisfaction was measured with a structured Satisfaction With Life Scale (SWLS). Nonparametric bivariate analyses and multivariable adjusted generalised linear model (GLM) were used to examine the differences between mean SWLS scores and examined variables. We included 134 US-trained specialists, 134 Taiwan-trained specialists, and 134 general dentists matched for age, sex, and marital status. RESULTS: With the mean age of 51.4 ± 10.8 years old, specialists had significantly higher mean life satisfaction scores than general dentists. US-trained specialists had significantly higher mean life satisfaction scores than Taiwan-trained specialists when health and family relationships were not considered. Career-rated factors (eg, spending more clinical hours with patients, having more expenses related to continuing education, publishing more peer-reviewed articles, and being a frequent speaker) were not associated with better life satisfaction. CONCLUSIONS: US-trained specialists were more likely to be satisfied with their lives than Taiwan-trained specialists and general dentists. However, health and social relationships contribute more to dentists' life satisfaction than do career-rated factors.

Cyanidin-3-O-glucoside downregulates ligation-activated endoplasmic reticulum stress and alleviates induced periodontal destruction in rats.

OBJECTIVE: Cyanidin-3-O-glucoside (C3G), a dietary anthocyanin, possesses various biological properties, including alleviating endoplasmic reticulum (ER) stress. This study examined the effect of C3G on periodontitis via ER stress in rats. DESIGN: Periodontitis was induced by placing silk sutures around maxillary second molars. C3G (0, 3, or 9 mg/kg) was fed on the day before ligation (10 rats/group). Further, 10 non-ligation control rats received deionized water. On day 8, gingivae were obtained to determine CCAAT/enhancer-binding protein homologous protein (CHOP), c-Jun N-terminal kinase (JNK), phospho-JNK (p-JNK), and nuclear factor-κB (NF-κB) by immunoblotting. Periodontal destruction was evaluated using micro-computed tomography (µCT) and histology. RESULTS: Gingival expression of CHOP, p-JNK/JNK, and NF-κB significantly increased in ligation rats (0 mg/kg C3G) than that in controls. However, protein expression in ligation groups presented a negative association with C3G concentration. By µCT, the distance of cemento-enamel junction to bone significantly increased in ligation groups; however, distances showed a negative association with C3G concentration. In the region of interest, bone volume and trabecular thickness and number significantly decreased in ligation groups but they were positively associated with C3G concentration. In terms of trabecular separation, opposite results were found. Histologically, infiltrated connective tissue (ICT) and periodontal destructions increased in ligation groups; however, they were negatively associated with C3G concentration. Moreover, ICT area is positively correlated with µCT- and histologically measured destructions and protein expression of CHOP, p-JNK/JNK, or NF-κB. CONCLUSION: C3G promotes favorable modulation of ER stress and alleviates destruction of periodontitis, which may imply a new strategy.

Is periodontitis a risk factor of benign or malignant colorectal tumor? A population-based cohort study.

OBJECTIVE: To examine the risk of developing benign or malignant colorectal tumors in patients with periodontitis within 15 years using Taiwan's National Health Insurance Database. BACKGROUND: Studies have shown that colorectal carcinoma often develops under inflammatory conditions and changes of microbiota in the gut. Recently, a link between Fusobacterium nucleatum, a periodontal pathogen, and colorectal carcinoma has been proposed. However, whether periodontitis is a risk of developing colorectal tumor remains uncertain. METHODS: In total, 35 124 participants were enrolled from 2000 to 2015 to examine the development risk of benign colorectal tumors, including 11 708 patients with periodontitis who received therapy (group 1), 11 708 patients with periodontitis not receiving periodontal treatment (group 2), and 11 708 non-periodontitis controls after matching for gender, age, and index year. To examine the risk of developing colorectal malignancy, 11 720 participants were assigned to each of the three groups. Cox proportional hazards model and Kaplan-Meier methods were used to compare the risks. Sensitivity analysis was performed, excluding the diagnoses during the first 1 or 5 years. RESULTS: After the follow-up, 177, 154, and 63 participants in group 1, group 2, and control group had benign colorectal tumors. Patients with periodontitis tended to be associated with a greater rate of having a benign colorectal tumor. The adjusted hazard ratios (aHRs) were 3.77 (95% confidence interval [CI] 2.01-4.82, p < .001) and 2.85 (95% CI 1.62-3.74, p < .001) for groups 1 and 2, respectively. Regarding the risk of malignant colorectal tumor, 20, 18, and 14 participants who developed malignant tumors were included in group 1, group 2, and control group; however, no significant increase in malignancy was observed in periodontitis groups (aHR1.92, 95% CI 0.74-2.36, p = .482; aHR 1.50, 95% CI 0.68-1.97, p = .529, for the two periodontitis groups, respectively). CONCLUSIONS: The results of this study suggest that patients with periodontitis may have an increased risk of developing benign, but not malignant, colorectal tumors.

Bone formation with functionalized 3D printed poly-ε-caprolactone scaffold with plasma-rich-fibrin implanted in critical-sized calvaria defect of rat.

BACKGROUND/PURPOSE: Space-making is one of the essential factors for bone regeneration in severe bony defect. To test the hypothesis that an appropriately designed scaffold may be beneficial for the bone formation in defect, the new bone formed in the critical-size calvarial defect of rat was examined after implanted with a 3D-printed poly-ɛ-caprolactone (PCL) scaffold, retaining with and without plasma rich fibrin (PRF). MATERIALS AND METHODS: Thirty-two rats were divided into four groups (control, PCL, PRF, and PCL-plus-PRF). A custom-made 3D-printed PCL scaffold, 900 µm in pore size, retaining with and without PRF, was implanted into a critical-sized calvarial defect, 6 mm in diameter. Animals were sacrificed at week-4 or 8 after implantation for assessing the new bone formation by dental radiography, micro-computed tomography (µ-CT), and histology. RESULTS: By radiography and µ-CT, significantly greater mineralization areas/volumes were observed in defects with 3D-printed scaffold groups compared to that without the scaffold in both two-time points. However, no advantage was found by adding PRF. Histology showed that bone tissues grew into the central zone of the critical defect when 3D-printed PCL scaffold was present. In contrast, for the groups without the scaffolds, new bones were formed mostly along defect borders, and the central zones of the defects were collapsed and healed with thin connective tissue. CONCLUSION: Our results suggest that the use of a 900 µm pore size 3D-printed PCL scaffold may have the potential in facilitating the new bone formation.

Life satisfaction of Taiwanese dental graduates received residencies in the U.S.: a cross-sectional study.

BACKGROUND: Each year, more than 200 international dental graduates start U.S. specialty trainings to become specialists. It is unknown if their life satisfaction is associated with any dental career-related factor before residencies (e.g. dental school class rank, research experience, or private practice experience) and after residencies (e.g. staying in the U.S., teaching status, workplace, or board certification). This cross-sectional study aimed to identify these potential factors by surveying Taiwanese dental graduates who pursued U.S. residencies. METHODS: Life satisfaction was measured with a structured questionnaire, Satisfaction With Life Scale (SWLS), which includes five statements on a 5-point Likert scale. Online surveys were sent out to 290 Taiwanese dental graduates who were known to pursue U.S. residencies. T-test, one way analysis of variance, and multivariable adjusted generalized linear model (GLM) were used to assess the differences of mean SWLS scores from different variables. RESULTS: Surveys were completed by 158 dentists. Mean SWLS score of 125 specialists was higher (p = 0.0007) than the score of 33 residents. For the 125 specialists, multivariable adjusted GLM demonstrated better life satisfaction was positively associated with multiple independent factors, such as having research experience, being ranked in the top 26 ~ 50% of the class in dental school, starting U.S. residency within 4 years after dental school, starting residency before year 1996, and specializing in endodontics (vs. periodontics). Life satisfaction was not associated with any factors after residency (e.g. staying in the U.S. afterwards, teaching status, or workplace), but better mean life satisfaction score was significantly associated with being American specialty board certified (p < 0.001) for the specialists in the 26 ~ 75% of their class in dental school. For the 33 residents, better mean life satisfaction score was associated with better dental school class rank in both bivariate (p = 0.020) and multivariable adjusted GLM (p = 0.004) analyses. CONCLUSIONS: The life satisfaction of Taiwanese dental graduates pursuing U.S. residencies might be associated with some professional factors, such as research experience, dental school class rank, residency timing, specialty type, and specialty board certification. We hope our results may provide some objective information on making career decisions for international dental graduates/students who are preparing for U.S. residency.

Electroacupuncture Promotes Neural Proliferation in Hippocampus of Perimenopausal Depression Rats via Wnt/ß-Catenin Signaling Pathway.

BACKGROUND AND OBJECTIVE: Perimenopausal depression is caused by the impaired function of the ovarium before menopause and with a series of symptoms. Electroacupuncture (EA) therapy has been demonstrated to improve clinically depression. However, the mechanism underlying its therapeutic activity remains unknown. This study aimed to investigat the effects of EA treatment on the hippocampal neural proliferation through Wnt signaling pathway. METHODS: Chronic unpredictable mild stress (CUMS) combined with bilateral ovariectomy (OVX) were used to establish a rat model of perimenopausal depression. The open field test (OFT) and sucrose preference test (SPT) were used to assess depression-like behaviors in rats. ELISAs were used to measure estrogen (E2), luteinizing hormone (LH) and gonadotropin-releasing hormone (GnRH) levels in the serum. RT-PCR and Western blot assay were utilized for measuring the mRNA expressions and protein expressions of GSK-3ß/ß-catenin. RESULTS: Four-week EA treatment at three points including "Shenshu" (BL23), "Baihui" (GV20) and "Sanyinjiao" (SP6) simultaneously ameliorated depression-like behaviors in rats with CUMS and OVX, whereas rescued the decreased serum level of E2 and prevented the increased serum levels of GnRH and LH. EA treatment ameliorated CUMS and OVX-induced alterations of glycogen synthase kinase-3ß (GSK-3ß) and ß-catenin mRNA levels, ß-catenin and phosphorylated ß-catenin (p-ß-catenin) protein levels. CONCLUSIONS: The results showed that EA treatment promoted hippocampal neural proliferation in perimenopausal depression rats via activating the Wnt/ß-catenin signaling pathway, indicating that EA may represent an efficacious therapy for perimenopausal depression.

CD147 self-regulates matrix metalloproteinase-2 release in gingival fibroblasts after coculturing with U937 monocytic cells.

BACKGROUND: Cluster of differentiation 147 (CD147) is a multifunctional glycoprotein that functions as an inducer of matrix metalloproteinase (MMP) expression in fibroblasts. Synergistically enhanced MMP-2 expression was recently observed in the coculture of human gingival fibroblasts (HGFs) and U937 human monocytic cells; however, the responsible mechanisms have not yet been fully established. The aim of this study was to evaluate the release of soluble CD147 in HGFs after coculturing with U937 cells and its functional effect on the enhancement of MMP-2 expression in HGFs. METHODS: Enzyme-linked immunosorbent assay was used to determine the amount of CD147 protein in media, whereas real-time polymerase chain reaction was performed to evaluate the mRNA levels of CD147 and MMP-2 in HGFs and U937 cells. The enzyme activities of MMP-2 released from cells were examined by zymography. Transwell coculturing and conditioned media treatments were selected to rule out the effect of direct contact of HGFs and U937 cells. RESULTS: The protein and mRNA expression of CD147 in HGFs were enhanced after transwell coculturing with U937 cells and exposure to U937-conditioned medium. MMP-2 enzyme activities in HGFs were also significantly increased by the coculturing methods. Administration of exogenous CD147 enhanced MMP-2 expression in HGFs, whereas treatment with cyclosporine-A, which inhibited CD147 expression, reduced U937-enhanced MMP-2 expression in HGFs. CONCLUSIONS: CD147 can interact with fibroblasts to stimulate the expression of MMPs associated with periodontal extracellular matrix degradation. This study has demonstrated that CD147 released from fibroblasts might play a role in monocyte-enhanced MMP-2 expression in HGFs.

Zfp423 Regulates Skeletal Muscle Regeneration and Proliferation.

Satellite cells (SCs) are skeletal muscle stem cells that proliferate in response to injury and provide myogenic precursors for growth and repair. Zfp423 is a transcriptional cofactor expressed in multiple immature cell populations, such as neuronal precursors, mesenchymal stem cells, and preadipocytes, where it regulates lineage allocation, proliferation, and differentiation. Here, we show that Zfp423 regulates myogenic progression during muscle regeneration. Zfp423 is undetectable in quiescent SCs but becomes expressed during SC activation. After expansion, Zfp423 is gradually downregulated as committed SCs terminally differentiate. Mice with satellite-cell-specific Zfp423 deletion exhibit severely impaired muscle regeneration following injury, with aberrant SC expansion, defective cell cycle exit, and failure to transition efficiently from the proliferative stage toward commitment. Consistent with a cell-autonomous role of Zfp423, shRNA-mediated knockdown of Zfp423 in myoblasts inhibits differentiation. Surprisingly, forced expression of Zfp423 in myoblasts induces differentiation into adipocytes and arrests myogenesis. Affinity purification of Zfp423 in myoblasts identified Satb2 as a nuclear partner of Zfp423 that cooperatively enhances Zfp423 transcriptional activity, which in turn affects myoblast differentiation. In conclusion, by controlling SC expansion and proliferation, Zfp423 is essential for muscle regeneration. Tight regulation of Zfp423 expression is essential for normal progression of muscle progenitors from proliferation to differentiation.

Ameliorative effect of hesperidin on ligation-induced periodontitis in rats.

BACKGROUND: This study evaluated the ameliorative effect of hesperidin (HES), an anti-inflammatory flavanone, in rats with ligation (Lig)-induced periodontitis. METHODS: A total of 48 rats were randomly divided into non-ligation group (NL), Lig group, and two ligation-plus-HES groups (L+H). HES was administered immediately after ligature placement at a dose of 75 or 150 mg/kg by intragastric feeding. Destruction of the ligated maxillary second and mandibular first molars were evaluated by dental radiography, microcomputed tomography (micro-CT), and histometry performed after sacrificing the rats on the seventh day. The expression levels of interleukin (IL)-1ß, IL-6, and inducible nitric oxide synthase (iNOS) messenger (m)RNAs in the gingiva were determined by reverse-transcription polymerase chain reaction. The expression of iNOS was examined by immunohistochemistry. RESULTS: The dental radiography and micro-CT findings revealed significantly increased alveolar bone loss in the Lig group, which was significantly prevented by HES. The histometry results revealed less gingival inflammation and connective tissue loss in the L+H groups compared with that in the Lig group. The mRNA expression levels of IL-6, IL-1 ß, and iNOS were significantly increased in the Lig group but were reduced in the L+H groups. The immunostaining results showed that the ligation-induced iNOS expression was also decreased by HES. CONCLUSIONS: Oral administration of HES promotes an ameliorative effect against the ligation-induced alveolar bone loss and effectively inhibits the production of proinflammatory mediators in rats with experimentally induced periodontitis. Therefore, HES may be a good candidate for modulating oral inflammatory diseases.

Comparison of Beneficial Effects of Acupuncture at PC6, LU7 & Non- acupuncture Points on Cardiac Cell Function in Myocardial Ischemia (MI) Rats by Testing Protein Expression of L-type Calcium Channel Protein and its Related Protein.

The mechanism of why electro-acupuncture (EA) at PC6 improves the heart function was investigated by studying how the L-type cardiac voltage-dependent calcium channel in myocardial ischemia (MI) is regulated. Cava,., Cavo and Cava2-61 are main component proteins of L-type calcium channel; CaM and Calmodulin kinase II (CaMKII) are Ca2+ channel associated proteins. In this experiment, MI was induced by injection of isoproterenol (ISO) in rats and electrocardiograms (ECGs) were recorded before and after every injection, and protein expressions of Cava,c, Cavp, Cava2_61, CaM and CaMKII were higher [The protein expression increased 43.39%, 54.85%, 47.08%, 48.29% and 50.36% respectively] than the control rats significantly (p<0.05). After MI induction, the MI rats were divided into three groups, including PC6 (Neiguan-point), LU7 (Lieque-point) and Non-acupuncture-point group, which were acupunctured once a day for 7 days respectively. After EA at PC6, the protein expressions showed obvious decrease [EA at PC6: the protein expressions of Cava1c, CavP, Cava2-81, CaM and CaMKII decreased 26.36%, 27.58%, 25.21%, 27.21% and 26.61% respectively.] and they are all lower than MI rats significantly (p<0.05). After EA at LU7 and Non-acupuncture-point, the protein expressions showed no significant changes. The effect of EA at PC6 was significantly better than LU7 and Non- acupuncture-point (p<0.05). PC6 is an acupoint of the pericardium meridian, and the pericardium meridian, which corresponds to opioid system according to Li P's research, can affect the cardio-vascular function directly. LU7 is located on the lung meridian; it cannot affect the heart function directly although the lung is related to the heart in blood circulation function so PC6 showed the target treating effect of meridian specificity on regulating the L-type calcium channel in MI.

Attenuation of the progression of articular cartilage degeneration by inhibition of TGF-ß1 signaling in a mouse model of osteoarthritis.

Transforming growth factor beta 1 (TGF-ß1) is implicated in osteoarthritis. We therefore studied the role of TGF-ß1 signaling in the development of osteoarthritis in a developmental stage-dependent manner. Three different mouse models were investigated. First, the Tgf-ß receptor II (Tgfbr2) was specifically removed from the mature cartilage of joints. Tgfbr2-deficient mice were grown to 12 months of age and were then euthanized for collection of knee and temporomandibular joints. Second, Tgfbr2-deficient mice were subjected to destabilization of the medial meniscus (DMM) surgery. Knee joints were then collected from the mice at 8 and 16 weeks after the surgery. Third, wild-type mice were subjected to DMM at the age of 8 weeks. Immediately after the surgery, these mice were treated with the Tgfbr2 inhibitor losartan for 8 weeks and then euthanized for collection of knee joints. All joints were characterized for evidences of articular cartilage degeneration. Initiation or acceleration of articular cartilage degeneration was not observed by the genetic inactivation of Tgfbr2 in the joints at the age of 12 months. In fact, the removal of Tgfbr2 and treatment with losartan both delayed the progression of articular cartilage degeneration induced by DMM compared with control littermates. Therefore, we conclude that inhibition of Tgf-ß1 signaling protects adult knee joints in mice against the development of osteoarthritis.

Gelatinases and extracellular matrix metalloproteinase inducer are associated with cyclosporin-A-induced attenuation of periodontal degradation in rats.

BACKGROUND: The present study aims to examine the inhibitory effect of cyclosporin-A (CsA) on periodontal breakdown and to further explore the correlations of CsA-induced attenuation of periodontal bone loss with the expressions of gelatinases (i.e., matrix metalloproteinase [MMP]-2 and MMP-9) and extracellular matrix metalloproteinase inducer (EMMPRIN). METHODS: Forty Sprague-Dawley rats were randomly divided into four groups: 1) control; 2) CsA; 3) ligature (Lig); and 4) ligature plus CsA (Lig + CsA). The CsA group received 10 mg ⋅ Kg(-1) ⋅ d(-1) CsA for 8 days. The Lig group received silk ligature on selected molars. The Lig + CsA group received silk ligature and CsA treatment. The inhibitory effects of CsA on the ligature-induced periodontal breakdown was examined with microcomputed tomography (micro-CT) and histometric analyses to analyze the amount of attachment loss, crestal bone loss, connective tissue attachment, and the surface area with inflammatory cell infiltration. The effects of CsA on ligature-induced expressions of gelatinases and EMMPRIN in gingival tissues were examined with Western blotting and zymography, respectively. RESULTS: By micro-CT and histology, the Lig + CsA group had significantly more periodontal breakdown than the control and CsA groups but less periodontal breakdown than the Lig group. Consistent results were found for the expressions of gelatinases and EMMPRIN among the groups demonstrating that the Lig + CsA group had significantly less gingival protein expression of gelatinases and EMMPRIN than the Lig group. CONCLUSIONS: CsA inhibited the expressions of gelatinase MMPs and EMMPRIN and partially prevented the periodontal breakdown in ligature-induced experimental periodontitis. The CsA-induced attenuation of periodontal bone loss was strongly correlated positively with the expressions of MMP-2, MMP-9, and EMMPRIN in gingiva.

Role of transforming growth factor-beta1 in cyclosporine-induced epithelial-to-mesenchymal transition in gingival epithelium.

BACKGROUND: It has been proposed that cyclosporin A (CsA) may induce epithelial-to-mesenchymal transition (EMT) in gingiva. The aims of the present study are to confirm the notion that EMT occurs in human gingival epithelial (hGE) cells after CsA treatment and to investigate the role of transforming growth factor beta1 (TGF-ß1) on this CsA-induced EMT. METHODS: The effects of CsA, with and without TGF-ß1 inhibitor, on the morphologic changes of primary culture of hGE cells were examined in vitro. The changes of protein and messenger RNA (mRNA) expressions of two EMT markers (E-cadherin and alpha-smooth muscle actin) in the hGE cells after CsA treatment with and without TGF-ß1 inhibitor were evaluated with immunocytochemistry and real-time polymerase chain reaction. RESULTS: The epithelial cells became spindle-like, elongated, and disassociated from neighboring cells and lost their original cobblestone monolayer pattern when CsA was added. However, the epithelial cells stayed in their original cobblestone morphology with treatment of TGF-ß1 inhibitor on top of the CsA treatment. When CsA was given, the protein and mRNA expressions of E-cadherin and α-SMA were significantly altered, and these alterations were significantly reversed with pretreatment of TGF-ß1 inhibitor. CONCLUSIONS: CsA could induce Type 2 EMT in gingiva by changing the morphology of epithelial cells and altering the EMT markers/effectors. The CsA-induced gingival EMT is dependent or at least partially dependent on TGF-ß1.

Administrative trends in U.S. dental schools.

The aims of this study were to analyze the administrative trends in U.S. dental schools at the beginning and end of a thirteen-year period and to identify the predictive factors for those changes. Administrative trends were measured by the difference in the number of major administrative positions for 1997 and 2010 reported in American Dental Education Association (ADEA) and American Dental Association (ADA) publications. Secondary measures (program length, student enrollment, and tuition) were also gathered. The mean numbers of administrative positions per school significantly increased over the study period, while the mean number of clinical science departments per school significantly decreased. The change in the number of directors was positively correlated with the change in student enrollment, but inversely correlated with the change in number of vice/associate/assistant deans. The change in the number of clinical science departments was positively correlated with changes in student enrollment and out-of-state tuition, but inversely correlated with the change in in-state tuition. The number of all departments per U.S. dental school significantly decreased in this period. The schools that had consolidation of clinical science departments were less likely to have increases in student enrollment and out-of-state tuition, but more likely to have increases in in-state tuition.

Systematic review and meta-analysis of randomized controlled trials for the management of limited vertical height in the posterior region: short implants (5 to 8 mm) vs longer implants (> 8 mm) in vertically augmented sites.

PURPOSE: The aim of this study was to undertake a systematic review with meta-analysis on randomized controlled trials (RCTs) to compare the rates of survival, success, and complications of short implants to those of longer implants in the posterior regions. MATERIALS AND METHODS: Electronic literature searches were conducted through the MEDLINE (PubMed) and EMBASE databases to locate all relevant articles published between January 1, 1990, and April 30, 2013. Eligible studies were selected based on inclusion criteria, and quality assessments were conducted. After data extraction, meta-analyses were performed. RESULTS: In total, 539 dental implants (265 short implants [length 5 to 8 mm] and 274 control implants [length > 8 mm]) from four RCTs were included. The fixed prostheses of multiple short and control implants were all splinted. The mean follow-up period was 2.1 years. The 1-year and 5-year cumulative survival rates (CSR) were 98.7% (95% confidence interval [CI], 97.8% to 99.5%) and 93.6% (95% CI, 89.8% to 97.5%), respectively, for the short implant group and 98.0% (95% CI, 96.9% to 99.1%) and 90.3% (95% CI, 85.2% to 95.4%), respectively, for the control implant group. The CSRs of the two groups did not demonstrate a statistically significant difference. There were also no statistically significant differences in success rates, failure rates, or complications between the two groups. CONCLUSION: Placement of short dental implants could be a predictable alternative to longer implants to reduce surgical complications and patient morbidity in situations where vertical augmentation procedures are needed. However, only four studies with potential risk of bias were selected in this meta-analysis. Within the limitations of this meta-analysis, these results should be confirmed with robust methodology and RCTs with longer follow-up duration.

Association of CCL5 and CCR5 gene polymorphisms with periodontitis in Taiwanese.

BACKGROUND: It has been suggested that genetic factors may predispose individuals to periodontal diseases. The present case-control study aims to test whether the -403 single nucleotide polymorphism of chemokine ligand 5 (CCL5-403) and the 32-bp deletion of CCR5 (CCR5Δ32) polymorphisms are associated with susceptibility to chronic and aggressive periodontitis. METHODS: Taiwanese participants (N = 213) were grouped into control group (CG), generalized aggressive periodontitis (GAgP), or chronic periodontitis (CP) groups. DNA samples were obtained from peripheral blood. CCL5-403, evaluated by polymerase chain reaction-restriction fragment length polymorphism, and CCR5Δ32, evaluated by polymerase chain reaction, were compared among the three groups. RESULTS: There was a significant association between type of periodontitis and having allele A or G in the CCL5-403 polymorphism. GAgP patients were 3.7 times more likely than CP patients and 2.0 times more likely than CG patients to have allele A, instead of allele G, in CCL5-403. GAgP patients were 3.1 times more likely than CG patients to have AG versus GG genotype. GAgP patients were also 5.0 and 19.8 times more likely than CP patients to have AG and AA genotypes, respectively, compared to GG. For the CCR5Δ32 polymorphism, no association was found between the type of periodontitis and having different genotype or allele distributions among GAgP, CP, or CG patients. CONCLUSION: The single nucleotide polymorphism of CCL5-403 G substitution by A may play a role in AgP; however, the CCR5Δ32 polymorphism may not.

Configuration and corticalization of the mandibular bifid canal in a Taiwanese adult population: a computed tomography study.

PURPOSE: The configuration and degree of corticalization of bifid mandibular canals were examined using medical computed tomography (CT) images from 170 hemimandibles obtained from 308 Taiwanese adults. MATERIALS AND METHODS: The configurations of the bifid canals were assessed according to their anatomical position in relation to the ramus, molars, premolars, and mental foramen; their course (anterior/posterior or superior/inferior); the presence or absence of confluence with the main mandibular canal; and the presence or absence of penetration through the mandible to form an accessory foramen. The percentage of the canal length that was corticalized was measured. Two different classifications of bifid canals were also briefly summarized and compared. RESULTS: When bifid canals are present (41.2% of patients; 27.6% of hemimandibles), the bifid canals were primarily located in the ramus and retromolar regions (67.7%) running anteriorly (95.9%) and superiorly (95.9%) without confluence with the main mandibular canal (91.1%). Up to 16.5% of bifid canals form accessory foramina on the cortical surface of the mandible. Approximately 78% of the bifid canals have varied degrees of corticalization around the bifid canals. CONCLUSION: The configuration and course of 170 mandibular bifid canals were evaluated with CT images. The bifid canals were primarily located in the ramus and retromolar regions; however, 32.4% of the bifid canals were located in potential positions for dental implant placement. Most of the bifid canals ran anteriorly superior to the main mandibular canal, did not rejoin with the main mandibular canal, and diminished within the mandibular body. Approximately half of the bifid canals (45%) were completely corticated.

Direct transcriptional repression of Zfp423 by Zfp521 mediates a bone morphogenic protein-dependent osteoblast versus adipocyte lineage commitment switch.

Osteoblasts and adipocytes arise from a common mesenchymal precursor cell. The cell fate decision of a mesenchymal precursor cell is under the influence of molecular cues and signaling pathways that lead to the activation or repression of lineage-specific transcription factors. The molecular mechanisms determining osteoblast versus adipocyte lineage specificity in response to bone morphogenic protein (BMP) remain unclear. In this study, we describe the mechanism through which Zfp521 (ZNF521), a regulator of lineage progression in multiple immature cell populations, regulates lineage specification of mesenchymal progenitor cells during BMP-induced differentiation events. In vivo deletion or in vitro knockdown of Zfp521 in mesenchymal precursors resulted in increased expression of the adipocyte determinant factor Zfp423 (ZNF423). This was concurrent with the loss of histone H3K9 methylation and an increase in histone H3K9 acetylation at the Zfp423 promoter, which together are indicative of decreased gene repression. Indeed, we found that Zfp521 occupies and represses the promoter and intronic enhancer regions of Zfp423. Accordingly, conditional deletion of Zfp521 inhibited heterotopic bone formation in response to local injection of BMP2. In contrast, marrow adiposity within BMP2-induced bone was markedly enhanced in Zfp521-deficient mice, suggesting that precursor cells lacking Zfp521 differentiate preferentially into adipocytes instead of osteoblasts in response to BMP2. Consistent with a cell-autonomous role of Zfp521 in mesenchymal precursors, knockdown of Zfp521 in stromal cells prevented BMP2-induced osteoblast marker expression and simultaneously enhanced lipid accumulation and expression of adipocyte-related genes. Taken together, the data suggest that Zfp521 is a cell fate switch critical for BMP-induced osteoblast commitment and identify Zfp521 as the intrinsic repressor of Zfp423 and hence of adipocyte commitment during BMP-induced mesenchymal precursor differentiation.